Joy to the world, Justin Bieber has come, let the Jingle Ball receive its king. Although heaven and nature weren’t singing during his performance at radio station Z-100’s annual holiday extravaganza, the young girls, who packed Madison Square Garden, were.

At a concert featuring some of 2009’s biggest and youngest hitmakers — including Taylor Swift (who headlined the bill), guitar ace John Mayer, “American Idol” champ Kris Allen, as well as Boys Like Girls and the Fray — leave it to Bieber to have snagged top honors during his solo set and his star-crossed duets with Jordin Sparks and later with his mentor, R&B’s gentleman crooner, Usher.

For the oldsters saying “Justin Who?,” the kid is a 15-year-old Canadian discovered through YouTube. And if the pandemonium caused by his waving at the house was any indication, he is also the puppy-love desire of every ‘tween girl north and south of the boarder.

With his Yankees baseball cap askew (to show there’s a little bad boy in him) the kid had the hooks and looks to drive the girls wild, especially when he plucked a waif from her seat to sing her “One Less Lonely Girl.”

For those who prefer beer to bubble gum, the top musical moments of this four-hour concert lay in the duets. Eight-time Grammy nominee Taylor Swift and Martin Johnson of Boys Like Girls did the song “Two Is Better Than One.” Later Swift sparked John Mayer’s set when she joined him for a duet on “White Horse.”

Swift’s chirpy chipper voice added to both songs but was especially powerful in lending Mayersome crib-cred. Mayer felt every one of his 32 years. The house was slow to react to the goodness of his terrific tenor during the tune “Waiting for the World To Change,” and they seemed indifferent during his version of the blues classic “Crossroad.” Mayer uttered, “Somebody get the old dude off stage.”

Humor aside, he was right. Many in the audience pretended that they were too big to believe in Santa, but this show was best when it was by kids for kids.